Evidence from Switzerland suggests that prescribing heroin can reduce crime and increase levels of employment among addicts. While still illegal in the UK, cannabis was downgraded to a category C drug in January 2004. Would drug legalisation really reduce crime overall, and would it make drug use any safer?

Based on rigorous research and interviews with experts, the programme hears the arguments for leaving the most dangerous drug of all – crack cocaine – illegal, and examines how a legal and regulated system of drugs would work.

It is 2015. In the film, an ex-drugs policeman investigates two girls’ deaths. The government, persuaded by the vast economic cost of prohibition, has decided to legalise drugs. The UK, along with a coalition of progressive countries from Europe, Canada and Australia, has opted out of the UN treaties which control drugs. Much of the trade from possession to use, and production to supply, has been legalised.

The drama opens with the collapse and subsequent deaths of two girls in a club which is licensed to sell drugs. In the scenario, most drugs are readily available, with government health warnings and lists of ingredients, from various outlets. Drugs of addiction, like heroin, are free but only available on prescription from Swiss-styled heroin clinics.

Cocaine is still illegal. The whole trade is regulated by a new agency, called Ofdrug. The film follows the investigation into the two girls’ deaths by an Ofdrug agent who works closely with an ex-drugs policeman. Experts such as former chief constable Francis Wilkinson argued the case for pro-legalisation, while David Raynes of the National Drug Prevention Alliance was one of the voices arguing against.